This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The primary aim of this study is to establish the inter-observer and measurement error of a new air displacement plethysmographer used to measure infant body fat (the "Pea Pod") and anthropometric measures in term and pre-term infants.